Biotechnology promises to revolutionize everything from agriculture to modern medicine. For example, methods of genetically engineering plants are being explored to increase productivity through greater drought and insect resistance as well as increased yields. In addition, plants are being examined as potential biofactories for the production of proteins (e.g., antibodies) and other compounds for use in human and veterinary medicine. However, a limited number of promoters exist for driving expression of a gene product of interest in plants. Some of these are effective at driving expression in only some plants. Others are effective at driving expression in some tissues and/or cells, but not others.